Arylaminoacenaphthenes as antioxidants for polyalkylene glycol compositions



dines, p-aminobiphenyl,

. I 2,938,058 ARYLAMINOA'CENAPHTHENES AS ANTIOXI- DANTS FOR POLYALKYLENE GLYCOL COMPOSITIONS v Samuel W. Tinsley, South Charleston, and John T. Fitzpatrick, Charleston, 'W. Va., Eassignors to Union Carbide Corporation, a corporation of New York No Drawing. Original application Feb. 10, 1956, Sen

1 .No. 564,629. Divided and this application May 15,

1958, Ser. No. 735,385 I I I 2 Claims. or. 260-6115) This invention relates to novel arylaminoacenaphthene compounds and uses thereof. This application is a d-ivisional application-of Serial No. 564,629, filed February 10, 1956, and now abandoned.

The preparation of arylaminonaphthalene derivatives by the reaction of an arylamine with a naphtholor naphthylamine is well known. Such reactions are carried; out

in the absence of a solvent, as for example inthe synthesis of l-anilinonaphthalene by the reaction of aniline with l-naphthylamine at reflux in the presence of sulfanilicv acid as catalyst, or they may be carried out in, aque- 'ous medium, as'for'example inthe synthesis of.2-p;tolyl- 1 with an arylamine'at an elevatedtemperature for a prolonged period of time. By the term' arylamine is meant a primary monoamino aromatic compound. I

The arylamines useful in "this invention are. aniline and its derivatives and naphthylamine and its, derivatives The'substituents on the anilineandrnaphthylamine de- U ited States Patent rivatives can be aryl such as a phenyl radical or alkyl having from '1 to about 3 carbon atoms,ioralkoxy having from 1 to-about 3 carbon atoms, or ahydroxy group;

Illustrative of the arylamines suitable in thisinvention are aniline, the toluidines, the anisidines, the xylimethyl naphthylamines. I

The reaction can be carried out by heating a mixture of 5-aminoacenaphthene with the selected arylamine at about the reflux temperature of the reaction mixture-until apractical conversion to 5-arylarninoacenaphthene hastalcenipla'ce. The reaction temperature will; vary depending-011 theboiling pointof the-starting reaction mixture, but it should not be so high that decomposition of the starting materials will occur; Therefore, a temperature below about 320 C. is preferred.

Theoretically one mole of the arylamine derivative will .react with one mole of 5-aminoacenaphthene. However,

in order to obtain practical yields, and also to serve as a diluent, it is preferred to use more than a stoichio metric amount of arylamine. Therefore, a molar ratio of arylamine to S-aminoacenaphthene of at least about 1.25:1 is recommended. Less than stoichiometric amounts are not recommended as it only tends to limit the yield, while excessively large amounts are wasteful and complicate separation of the desired arylaminoacenaphthene.

In order to hasten the reaction a catalyst is added at a concentration of about 1% by weight based on the total weight of the reaction mixture; Among the catalysts suitable in this reaction are sulfanilic acid, sulfuric acid and toluene sulfonic acid,

beta-naphthylamine and the Patented May2 4', :1960

The S-arylaminoacenaphthene compounds of thisfinvention can be represented by the general formula wherein Ar is an aryl radical such as and wherein R and R can be hydrogen, or alkyl containing from 1 to about 3 carbon atoms, or alkoxy having from 1 to about 3 carbon atoms, or hydroxyl, or phenyl radicals. Where R or R" is a phenyl radical it is located at any position except ortho to the position at which the Ar :group is attached to the'nitrogen a'tom;

In an embodiment of this invention 1 mole of 5- aminoacenaphthene is reacted with 1.5 mole of aniline and a catalytic amount of .sulfanilic acid at .thereflux temperature of the reaction mixture, about 200m 220 C., for about 7.5 hours. .At the end of thisperiodthe mixture is fractionally distilled under vacuum and the S-anilinoacenaphthene recovered in the distillation is further purified by recrystallization from boiling ethanol.

The compound Seanilinoacenaphthene is an excellent antioxidant for polyalkylene glycol lubricants andlubri-" cants consistingof the monoor (ii-ethersof .thepolyalkylene glycols. These lubricants are of great industrial importance be- .cause of their desirablet physical"andchemicallproperties and stability over awidetemperature range. The'yhave been successfullyemployed as'lubricants in compressors, power recovery engines and vacuum pumps handling air, hydrogen, nitrogen, and hydrocarbons, l'as well as in equipment used for fabricating products from red-hot .metal ingots andzin the glass 'andceramic' industries; where dures to-yield products ranging .in average molecular weight from about 250 up to' above about 6000 as clear colorless liquids. In U.S. Patent 2,425,755 is disclosed a method of preparing the monoethers of the polyalkylene glycols having average molecular weights up to about 3000 by reacting a mixture of ethylene oxide, propylene oxide and a monohydric alcohol. U.S. Patent 2,425,845 demonstrates the preparation of polyalkylene glycols having average molecular weights up to and above about 6000 by reacting a mixture of ethylene oxide, propylene oxide and a dihydroxy alcohol. The monoethers of polypropylene glycol having average molecular weights up to about 2000 are prepared by the reaction of a monohydric alcohol with 1,2-propylene oxide as described in U.S. Patent 2,448,664. 2,520,611 and 2,520,612 are described methods for preparing diethers of polyalkylene glycols having average molecular weights up to about 2000 by reacting diethyl, sulfate with a monoether of a polyalkylene glycol.

cants have an appreciable stabilizing effect as indicated In U.S. Patents -by weight. Lesser quantities are not very effective as'vvill be seen in Table I. For comparison purposes an example using l-anilinonaphthalene, a conventional anti-oxidant, is included in the table.

TABLE I Antioxidant, percent by 0.5% A 0.1% B 0.25% B. 0.5% B.

wt. added to lubricant. Condensate after hrs. of 11.7. 201111.111 18.7.-. al'ew oxidation, ml. 7.1 hrs. drops. Kenemetic viscosity, Cs.:

(1:) at 100 F.-

atstart 63.33-..- 62.22 62.54-... 63.51. alter 10hrs.oxid.. 60.14..-- 60.87 63.78.... 64.84. percentchange 5.04- 2.18...-. 1.98 2.06. (b) at 210 F.-

atstart 10.96- 10.96...- 10.97-... 10.90. aiter10hrs.oxid--- 9.63-.--. 9.42"--. 9.74..--- 11.33. percentchange-. 12.1... -14.1...- 11.3... 3.1. Acldl number, mg. KOH/g.

at start 0.198---- 0.148 0.172---- 0.149. after10hrs.0xid 18.6-.- 21.2-..- 22.7..-.. 1.43.

A. l-anllinonaphthalene. B. 5-anilinoacenaphthene. t'zlglonobutyl ether of polypropylene glycol-Saybolt viscosity at 100 F. o 5.

It can readily be seen that at a concentration of 0.5%

by weight of S-anilinoacenaphthene in the lubricant that per minute for a period of ten hours. During this time A three-necked Pyrex flask equipped with a stirrer, therometer and reflux condenser was charged with 85 grams of S-aminoacenaphthene, grams of aniline and 1.5 grams of sulfanilic acid. The temperature of the re action mixture was raised to about 200 C., at which point reflux started, and the reaction was refluxed for 4 7% hours. At the end of this period the reflux temperature was 220' C. The reaction mixture was vacuum distilled and there was recovered 36 grams of unreacted aniline at 79 to 83 C. at a pressure of 20 mm. of mercury. Then at 188 to -192? .C..at a pressure of 1 mm. of mercury there was recovered grams of S-anilinoacenaphthrie. This was dissolved in boiling ethanol, slowlycooledlto'roomtemperature to crystallize and a crop of colorless crystals of S-anilinoacenaphthene which had a melting point of 129 to 130.5 C. was tilteredoif.

Example 2 The procedure of Example 1 was repeated using 85 grams of 5-aminoa'cenaphthene, 80 grams of p-toluidine and .1.5 grams of sulfanilic acid. Over a 6 hour reflux period the reaction temperature went from 215 C. up to 235 C. At the end of this period there was recovered 43 grams of unreacted p-toluidine at to 90 C. at a pressure of 20 to 2.5 mm. of mercury and 10 grams of unreacted S-aminoacenaphthene at 90 to 210 C. at a pressure of 2.5 mm. of mercury. Then at 217 to 235 C.

at a pressure of 3 mm. of mercury there was obtained 86 grams of 5-(4-methylanilino)-acenaphthene. This was recrystallized from boiling ethanol to yield 64 grams of almost colorless crystals of 5-(4-methylanilino)-acenaphthene having a melting point of 117 to 118 C.

Example 3 A mixture of the monobutyl ether of polypropylene glycol, having a Saybolt viscosity at F. to 285, and S-anilinoacenaphthene was prepared by a simple mixing operation. The concentration of the 5-anilinoace naphthene was 0.5 by weight. This composition was then tested for resistance to oxidation by the Bulk Oxidation Test hereinbefore described. The kinematic viscosity and acid number were determined before and after the oxidation period. For comparison purposes a similar composition was prepared using 0.5 by weight of l-anilinonaphthalene, a conventional antioxidant. Results were tabulated supra in Table I.

We claim:

1. A composition of matter comprising a polyalkylene glycol having an average molecular weight of 'at least about 250 in admixture with from about 0.1 to about 2% by weight of S-anilinoacenaphthene.

2. A composition of matter comprising a lower alkyl ether of a polyalkylene glycol having an average molecular weight of at least about 250 in admixture with from about 0.1 to about 2% by weight of S-anilinoacenaphene.

References Cited in the file of this patent UNITED STATES PATENTS 1,809,799 Clifford June 9, 1931 2,481,278 Ballard et a1 Sept. 6, 1949 2,520,733 Morris et a1. Aug. 29, 1950 2,641,614 Britten et a1. 'June 9, 1953 

1. A COMPOSITION OF MATTER COMPRISING A POLYALKYLENE GLYCOL HAVING AN AVERAGE MOLECULAR WEIGHT OF AT LEAST ABOUT 250 IN ADMIXTURE WITH FROM ABOUT 0.1 TO ABOUT 2% BY WEIGHT OF 5-ANILINOACENAPHTHENE. 